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Isolated ac hood ventilation questions

JSB99

Well-Known Member
Before I buy anything, I'm considering isolating my hood air from my 4x4 tent w/600w HID. If I went this route I'd be drawing the hood air from under the house using a 440cfm fan. My room/house has central AC set at 68/Winter, 73/summer.

My questions are:
  1. Can I exhaust the hood air directly into the attic or should I still vent it outside?
  2. Would a 4"/200cfm fan/filter be adequate to vent the tent, or should I use a 2nd 6" fan/filter?
  3. Would I still need to get a window AC for the room, or would I just need a dehumidifier?
  4. In the Winter, when it's fairly cold outside, does that cold air have any negative effects on the lamp?


Thanks for the feedback!
 

JSB99

Well-Known Member
I'm not trying to create a sealed room out of a tent, which I know isn't possible, and I'll never inject co2. I'm just looking to take the light heat out of the equation. Since I have central AC, I hate the thought of exhausting it and how inefficient that is. If I go this route, I would use a 4" inline fan and retrofitted ac filter to swap the room air with the house on an incremental timer.

I'm thinking that I could run some extra ducting for winter where the hood intake and exhaust are both connected to another room in the house. That way I could use the light to help warm the home, but without adding the humidity from the tent. I'm sure others do this if it works.
 
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Budley Doright

Well-Known Member
I'm kind of high but could you not use a cool tube to bring in air and exhaust from the house, this would heat the house if needed. Then run intake and exhaust, on separate fan, outdoors, or from the house for extra cooling when needed. It would be nice to switch the pipes as needed for extra heating when heating season and outdoors when cooling season. I've never had an issue running cold air over the light but I also only had fan on when light fired up. I now just use gull wings. This probably makes no sense.
 

JSB99

Well-Known Member
I'm kind of high...
Well it's a good thing I'm kinda high reading this. I'll probably understand you better lol

...but could you not use a cool tube to bring in air and exhaust from the house, this would heat the house if needed. Then run intake and exhaust, on separate fan, outdoors, or from the house for extra cooling when needed. It would be nice to switch the pipes as needed for extra heating when heating season and outdoors when cooling season.
Heating the house in the Winter was kind of an afterthought, but the multiple ducts for the season is what I was thinking as well.

I've never had an issue running cold air over the light but I also only had fan on when light fired up.
I've read a couple places that cold air running across the bulb drops the voltage, effecting the output. While that may be true, I imagine having the ability to get your light close to the canopy makes up for it.

could you not use a cool tube? I now just use gull wings.
I'm going to be using a regular-sized ac hood, since I'll have the space. The cool tubes don't have the footprint of the larger reflectors.

What I was really trying to find out is, if I've isolated the hood from the grow by using outside air, will a 4" inline fan (say 200 cfm), and a 4" scrubber be enough to cycle the 4x4x7 tent air with the room air, incrementally.

I've built a few grows, so I know about keeping temps at bay, but not with the hood ventilation separate from the grow. What I don't know is how much radiant heat is left in the tent to deal with. How warm, and how quickly, does the tent get, even with the light heat removed? Would the tent temps stay relative to the room, to where I could cycle the air on a 15 minute timer with a 4" fan?

I was also wondering if I'd need a window ac if I've got the light heat isolated. Does the tent/room still get warm with that setup?
 
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Budley Doright

Well-Known Member
It will probably work until the temps outdoors rise above high 60's, I think you may need mech. cooling at that point. It's really hard to say but I run 1000w and right now I keep the 8x8x8 shed at 74-5 by cycling 300cfm ducted to the top of the reflectors. Mind you it's still pretty cold here, with temps outside at 50. When the temps rise above 70 I struggle to keep things cool.
 

JSB99

Well-Known Member
It will probably work until the temps outdoors rise above high 60's, I think you may need mech. cooling at that point. It's really hard to say but I run 1000w and right now I keep the 8x8x8 shed at 74-5 by cycling 300cfm ducted to the top of the reflectors. Mind you it's still pretty cold here, with temps outside at 50. When the temps rise above 70 I struggle to keep things cool.
Seems dehumidifiers are as expensive as window ACs, so I'll just get an AC. Seeing used ones for $50-$100 on Craigslist.

It's pretty mild here in OR, but it still hovers in the 90s in the summer. Guess I'll have to see how much outside temps affect growing in the house w/central ac.

Thx
 

Budley Doright

Well-Known Member
That would be pretty hard to do lol. Cutting out and reinstalling evap coils is a hit and miss thing and most likely you would plug the cap tube. Then you need to sync the two units, one being a solid state board, not worth the effort IMO. This build saved me about $500-$600 if I bought a new chiller and this has a higher capacity. I may add a water fan coil next fall if I have capacity to spare :).
 

JSB99

Well-Known Member
Yeah, I guess that would be pretty difficult lol.

That chiller you built is really cool (no pun intended)! If I get bored with soilless and decide to build an rdwc/uc I might go this route over a chiller. Chillers are so over-priced! I want to run a Danner 18, so I'd want something pretty robust.
 

Budley Doright

Well-Known Member
Yeah, I guess that would be pretty difficult lol.

That chiller you built is really cool (no pun intended)! If I get bored with soilless and decide to build an rdwc/uc I might go this route over a chiller. Chillers are so over-priced! I want to run a Danner 18, so I'd want something pretty robust.
Well this has a coopernickle exchanger so will handle the nutrient solution even though I run glycol due to freezing, in the colder months I will run a fan cycling control to stop freeze ups and it is digitally controlled using a two stage Ranco control. If you ever do build one just let me know and I can guide you through most things. I'm a refrigeration mechanic so I do have all of the equipment on hand which helps lol.
 

JSB99

Well-Known Member
Well this has a coopernickle exchanger so will handle the nutrient solution even though I run glycol due to freezing, in the colder months I will run a fan cycling control to stop freeze ups and it is digitally controlled using a two stage Ranco control. If you ever do build one just let me know and I can guide you through most things. I'm a refrigeration mechanic so I do have all of the equipment on hand which helps lol.
Right on!

Thx
 

Budley Doright

Well-Known Member
Hey you have any info to go on when you made this? Or did you just know your shit with AC units and make it? Does it work well?
I know my shit and yes it works well so far at Day two lol. I just got a coaxial coil, 1 ton and where the evap coil was now there is a coaxial coil. The unit is controlled by a thermostat powered outlet that monitors res temp. But yes I have all of the stuff required like a reclaimer, nitrogen, vacuume pump, etc.
 

Budley Doright

Well-Known Member
I actually tried an old water cooler but it ran for about a minute lol. These units use cap tubes and unless you run nitrogen while welding it'll plug and even then it's hit and miss. .5-1 ton tx valve would be better and cut the cap tube the fuck out lol. Mine didn't make it here and I got bored lol
 

ALong14U

Well-Known Member
Damn I'm kinda following you but your knowledge of the units is far more than mine. I need a chiller. It's not super important but I am going to need it in about 12 months. I like to plan way ahead lol. I need something that will chill 40 gallon to 65 degrees and keep it there and never fluctuate. Thanks for the tips like that chiller for sure.
 

Budley Doright

Well-Known Member
Damn I'm kinda following you but your knowledge of the units is far more than mine. I need a chiller. It's not super important but I am going to need it in about 12 months. I like to plan way ahead lol. I need something that will chill 40 gallon to 65 degrees and keep it there and never fluctuate. Thanks for the tips like that chiller for sure.
Well I was going to buy one (used) for $300 but the guy sold it before I could arrange to go get it. I said fuck it and built my own. This will have no issues doing 75 gallons which is what I run at full speed. Here is a quick and easy formula

BTU = Gallons x Temperature Change (°F) x 8.33
 

ALong14U

Well-Known Member
Thanks for that
Well I was going to buy one (used) for $300 but the guy sold it before I could arrange to go get it. I said fuck it and built my own. This will have no issues doing 75 gallons which is what I run at full speed. Here is a quick and easy formula

BTU = Gallons x Temperature Change (°F) x 8.33
Thanks for that equation. I will use it for sure. Hope 50 galls will be enough might have to up it. Planning a DTW table with open ended bags then fill the table with hydroton and flood it 3x a day. Never DTW before so want to plan ahead and not fuck anything up lol. Appreciate it.
 
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